The only problem I see is signup with facebook, to be perfectly honest that's the reason you don't have a user extra (mine). While I do understand the choice, I think you should provide an alternative signup option.
It's also a bit unclear how much I get to keep when a user pays 25cents and how/when the money will reach me, if I would be implementing minno as a payment option I'd like to know...
For now, we're restricting sign-up to Facebook because it 1) allows for really easy signup, 2) reduces password friction to simplify purchases, and 3) helps us reduce fraudulent signups. As the business grows, we will certainly open it to alternative signup options, but for now, Facebook is the only option.
During our beta period, we're offering completely free transactions to all of our partners. This means that if a user pays $0.25 for your digital good/service, you will receive $0.25 :)
If you have any other questions, feel free to email me directly at calvin@minno.co--I'd be glad to help!
Calvin